The invention relates to piston-type machines, and particularly to machines provided with a conrod-free mechanism intended for transforming the translational motion of pistons to the rotary motion of an output shaft.
The term xe2x80x9cconrodxe2x80x9d as used herein means xe2x80x9cconnecting rodxe2x80x9d.
Hereinafter the term xe2x80x9cmachinexe2x80x9d means a device that is capable of performing functions of both an engine and a pump. The term xe2x80x9cenginexe2x80x9d means a device intended for transforming the energy of a working fluid to the mechanical energy, and particularly internal combustion engines, steam engines, hydraulic engines etc. The term xe2x80x9cpumpxe2x80x9d means a device intended for forcing or compressing fluids by mechanical means, and particularly both pumps for fluids and compressors for forcing compressible media, i.e. gases or vapors.
The inventive solution relates to a piston-type machine in the general meaning thereof, and may be used both in engines and in pumps.
Well-known in the art is the kinematic layout of the slider-crank mechanism, implementing a conrod-free mechanism intended for transforming the translational motion of pistons to the rotary motion of an output shaft. The layout comprises a housing member provided with two cylinders with mutually perpendicular axes; pistons with piston rods; sliders provided on piston rods; slider guide members; a carrier member, and an intermediate member engaged in rotary pairs with rods and with the carrier member.
In the course of reciprocal motion of pistons, the intermediate member pivotally connected to cylinder rods and the carrier member, carries out a complicated plane-parallel motion, thereby providing relationship between the motion of pistons and the rotation of the carrier member, with transformation of the reciprocal motion of pistons to the rotary motion of the carrier member without the use of connecting rods.
The above kinematic layout serves as a base for development of a conrod-free internal combustion engine known as xe2x80x9cBalandin enginexe2x80x9d (S. S. Balandin, Conrod-free Internal Combustion Engines, Moscow, Mashinostroyenie, 1968, pp.14-15). This engine comprises a housing member provided with cylinders; pistons with piston rods; sliders provided on piston rods; slider guide members each being connected to the housing member and made for displacing a corresponding slider along the axis of a corresponding cylinder; two coaxial carrier members mounted inside the housing member, and a crankshaft disposed between the carrier members, main journals of the above crankshaft being pivotally connected to carrier members, and rod pins, to relevant piston rods.
In the course of reciprocal motion of pistons, the crankshaft that is pivotally connected to cylinder rods and carrier members, carries out a complicated planetary motion by rotating around its own axis and the axis of carrier members, and provides the relationship between the reciprocal motion of the pistons and the rotation of the carrier members, with transformation of the reciprocal motion of pistons to the synchronous rotary motion of the carrier members without the use of connecting rods. Here, the main journals of the crankshaft are moving along a circle with a radius equal to xc2xc stroke of the pistons, while pistons and rods connected to the rod pins of the crankshaft are carrying out only.the rectilinear reciprocal motion along the stroke of pistons, without exerting any lateral thrust against cylinder walls. This mechanism may be used not only for internal combustion engines, but also for driven compressors, pumps, piston gas generators, and other piston-type machines. The engine with a similar kinematic layout is also described in SU, A1, 118471.
In the course of practical implementation of the above devices, there occurs the problem of design of guide members that would permit, when assembling the engine, to adjust these guide members to a position ensuring a coordinated motion of pistons inside cylinders and sliders/rods in the guide members without any distortions and jamming of the mechanism. This problem acquires a critical importance from the standpoint of the technological effectiveness of assembling of a piston machine, particularly a multicylinder piston machine.
Also known in the art is a piston-type machine disclosed in the specification to SU, A1, 1216271. This machine comprises a housing member provided with cylinders and having an axial hole; liners mounted inside the cylinders; pistons with piston rods, disposed inside the liners; sliders provided on piston rods; slider guide members each provided for displacement of a corresponding slider along the axis of a corresponding cylinder; two coaxial carrier members mounted inside the housing member, and a crankshaft disposed inside the axial hole of the housing member between the carrier members, main journals of the above crankshaft being connected to carrier members, and rod pins, with relevant piston rods. Slider guide members are made integrally with the liners and constitute an extension of the internal surface of the liner. That is, each of the guiding surfaces for a corresponding slide comprises a structural member of a corresponding liner, in which the guiding surface for the slider constitutes an extension of the internal surface of the liner.
The reciprocal motion of pistons in this known piston-type machine is transformed, through the rods with sliders moving within guide members, to the planetary rotary motion of the crankshaft that is pivotally connected to the rods and carrier members. The planetary motion of the crankshaft causes synchronous rotary motion of the carrier members. During machine operation in the engine mode, the power may be picked up from any carrier member or from an additional shaft being in kinematic relationship with the carrier members and providing synchronization of the rotary motion of the carrier members.
In this case, guide members for sliders are made non-adjustable. The accuracy of location of the guiding surfaces is ensured in the process of liner manufacture, since the slider guide members are made integral with the liners, constitute the extension of the liner internal surface, and are made in a single run.
However, in this embodiment of the piston-type machine the distance between the guiding surfaces restricting the displacement of each slider should not exceed the diameter of liners since the guiding surfaces of sliders constitute the extension of the liners internal surfaces comprising guiding surfaces for the pistons. From this, it follows that in the above design which inevitably provides the planetary motion of the crankshaft within the limits of the distance between the guiding surfaces of sliders, there exist restrictions for the eccentricity of a crankshaft, and hence for the stroke length of each piston. This circumstance substantially restricts the possibilities of using the above design in piston-type machines since it does not permit to provide a required ratio between the cylinder.diameter and the value of piston stroke length. It is of special importance in the designs of internal combustion engines, and particularly in diesel engines.
Known in the prior art are designs of piston-type machines provided with adjustable guide members of piston rods. Thus, known in the art is a crank mechanism of a piston type machine, disclosed in SU, A1, 1513259. This mechanism comprises a housing member with a cylinder; a piston with a piston rod; a slider provided on the piston rod; a slider guide member connected to the housing member and provided for slider displacement along the cylinder axis; a carrier member; and a con-rod pivotally connected to the slider and to the journal of the carrier member. Naturally, in a multipiston machine the above crank mechanism is repeated for each piston group. The slider guide member is shaped as a platelet mounted on the housing member for displacement and fixation in a selected position by means of screws and nuts. Suspended from this platelet by means of bolts and disk springs is a clamp member provided with solids of revolution. The solids of revolution are mounted on the clamp member for interaction with flat contact surfaces provided on the slider.
In this mechanism, the reciprocal motion of the piston is transformed to the rotary motion of the crankshaft via the rod provided with a slider that is moving in the guide member, and then via the con-rod. Here, flat contact surfaces of the slider interact with the solids of revolution that are fastened to the clamp member, transmitting the forces created thereby via disk springs and platelet to the housing member. In case of a need to adjust the position of a guide member, the platelet is moved by means of screws to a required position with respect to the housing member, following which the platelet is fixed in the selected position by means of nuts.
In the above design, the procedure of setting the guide members supposes manual adjustment of each guide member to the required position with respect to the axes of relevant cylinders and contact surfaces of sliders; therefore, under real conditions of assembling a piston-type machine it is practically impossible to attain a required accuracy of setting all the guide members to prevent jamming of the mechanism. In addition, the presence of console components and threaded joints in the power chain of the guide member restricts the use of the guide member under consideration under conditions of high dynamic loads, particularly in internal combustion engines, and especially in diesel engines.
Known in the art are practical designs of conrod-free internal combustion engines constructed in accordance with the xe2x80x9cBaiandin designxe2x80x9d. (S. S. Balandin, Conrod-free Internal Combustion Engines, Moscow, Mashinostroyenie, 1968, pp.28-75). These include a four-cylinder engine developed for the purpose of testing major kinematic and design properties of the conrod-free layout and performance of the conrod-free power mechanism in the engine system under actual loads, as well as standardized conrod-free engines having 140 to 400 hp power rating. Page 39 of this book contains the description of a four-cylinder, four-stroke gasoline engine of the aircraft type. This known engine comprises a housing member provided with cylinders, a front portion, a medium portion, and a back lid. The front portion accommodates the carrier member of a conrod-free mechanism, transmitting the engine power to a consumer, and a gas distribution mechanism. Mounted in the back lid is another carrier member of the conrod-free mechanism. The medium portion accomodates, between carrier members, a crankshaft with rods of the conrod-free mechanism. Main (extreme) journals of the crankshaft are connected to carrier members, and rod pins, to relevant piston rods. Each rod is provided with a slider that is mounted in guide members. Each guide member is connected to the housing member and is made for displacing a relevant slider along the axis of a corresponding cylinder. All the parts of the engine are connected therebetween by studs. Guide members for each slider are made as two separate segments, each segment being provided with a guiding surface and fastened to the housing member by means of bolted joints so that the guiding surfaces of the above segments, when being situated in parallel, form a guiding structure that ensures the motion of a corresponding slider along the axis of a relevant cylinder. Adjustment of guide members and provision of accuracy of such adjustment are carried out by hand, in the process of assembling, by fitting each segment to corresponding contact surfaces of sliders in a certain position, followed by fastening of segments to the housing member by means of bolted joints.
During the working cycle, each piston carries out reciprocating motion within a corresponding cylinder. Piston rods are moving together with pistons; in so doing, rod sliders are moving in the guide members through which they transfer resulting lateral loads to the housing member. Piston rods, being in the pivoted joint with the crankshaft, put it in the planetary motion during which the crankshaft rotates around its axis and around the axis of carrier members, thereby putting in the rotary motion the carrier members; each of these carrier members can be the output shaft of the engine.
The above design is complicated to assemble since it is required to fit each guiding segment, thereby ensuring the parallel arrangement of the guiding surfaces of segments and their orientation relative to the axes of corresponding cylinders. Precise adjustment of all the guiding segments, minimizing the probability of mechanism jamming, in this embodiment is extremely difficult and under real conditions of assembling a piston-type machine with conrod-free mechanism is practically unattainable.
The invention is based upon the object to develop an improved piston-type machine with conrod-free mechanism, in which design features would provide the possibility of self-adjustment of slider guide members to an optimal position relative to axes of corresponding cylinders in the course of assembling, thereby reducing the probability of jamming of the mechanism, improving the technological effectiveness of the resulting device, and substantially simplifying the assembling process.
The object set forth is attained in that in a piston-type machine with conrod-free mechanism, comprising a housing member provided with cylinders; pistons with piston rods; sliders provided on piston rods; slider guide members each being connected to the housing member and made for displacing a corresponding slider along the axis of a corresponding cylinder; two coaxial carrier members mounted inside the housing member, and a crankshaft disposed between the carrier members, main journals of the above crankshaft being pivotally connected to carrier members, and rod pins, to relevant piston rods, according to the invention, each guide member is made as a ring-shaped member with guiding surfaces, each ring-shaped member being mounted within, the housing member in coaxial relationship with carrier members for rotating around the axis of said carrier members, and provided with means for fixing position thereof relative to the housing member.
In the preferred embodiment of the invention, the guiding surfaces on each ring-shaped member may be formed by parallel surfaces of a groove provided in the diametral direction on one of the side surfaces of the ring-shaped member for displacement of the slider along said groove.
The means for fixing each ring-shaped member relative to the housing member are expedient to be provided as a screw joint, wherein a threaded hole is disposed in the ring-shaped member and the screw is mounted in a corresponding hole provided in the housing member, the diameter of said hole exceeding the diameter of said screw by 1.02 to 1.2 times.
In addition, it is also expedient to provide the means for fixing each ring-shaped member as a screw joint, wherein said threaded hole is disposed in the housing member and the screw is mounted in a hole provided in the ring-shaped member, the diameter of said hole exceeding the diameter of said screw by 1.02 to 1.2 times.
Providing slider guide members as ring-shaped elements, mounting the ring-shaped members within the housing member in coaxial relationship with carrier members for rotation around the axis of carrier members, and fixing position thereof relative to the housing member ensures the possibility of self-adjustment of the slider guide members relative to the axes of corresponding cylinders. In the process of assembling the inventive machine, the mounting of carrier members, crankshaft, pistons with piston rods, and slider guide members is followed by the motoring of the mechanism, during which the ring-shaped guide members, while rotating in mounting seats thereof around the axis of carrier members, independently occupy the most optimal position to prevent the jamming of the mechanism, following which they are fastened inside the housing member with the use of available means for fixing.